The research outlined in this project will test the effectiveness of a problem-solving strategy involving research-trained police officers as problem-solvers. Several targets of violence prevention have been identified; demonstration and research projects will aim at measurable impact on the problem. In addition to total measures of impact, the program will specifically test the effectiveness of the following experimental interventions: (1) Innovative recruit training aimed at violence reduction through subculture change; (2) Impact of peer group diagnosis of violence patterns and self-analytic peer interviews; (3) A family crisis intervention program with follow-ups and process monitoring; (4) A landlord-tenant intervention experiment, with legal input; and (5) A police-run re-education program for chronic police assaulters.